Trabeculectomy is recommended to treat glaucoma when more conservative treatment such as medication or laser do not provide adequate pressure control. In glaucoma, eye pressure causes damage to the optic nerve. With damage to the nerve, there can be irreversible loss of vision, and sometimes blindness. Fortunately, there are many excellent treatments for glaucoma that can prevent or stop vision loss. Generally we start treatment with medicated eye drops. Patients are treated with one or more drops to lower eye pressure. Unfortunately, drops don’t always lower eye pressure enough to protect a patient from further nerve damage and vision loss. Sometimes laser is an option, but laser does not work for everyone, and may not lower pressure enough. For that reason, a trabeculectomy is often the next step in treatment of glaucoma.
A trabeculectomy is a surgery designed to lower eye pressure to treat glaucoma. In a trabeculectomy, a new drain is created within the eye to allow fluid to leave the eye.This is done by removing a small piece of the natural drain in the eye and creating an opening in the sclera (the white of the eye) that is covered by a membrane on the surface of the eye (the conjunctiva). Fluid collects under the membrane (conjunctiva), forming a small elevation called a “bleb” that is under the upper eyelid.The fluid is then gradually absorbed into the body from the bleb
* Vision – Sight may take several weeks before it returns to normal . Some patients will find their vision is ot quiet as sharp after surgery. The benefit is slowing (or stopping) the rate of deterioration of glaucoma. However the operation cannot be totally guaranteed to stop the loss of vision in your eye. Eye surgery for any condition ALWAYS carries a small risk that vision may be worse or the eye may become bind after the operation.
* Eye pressure control – Failure to lower eye pressure enough, with the need for another operation of the need to recommend pressure lowering eye drops. If the eye pressure becomes too low after the surgery further surgery may be necessary
* Bleeding – There is a small chance of bleeding inside the eye immediately after the surgery ( called suprachoroidal haemorrhage) .This may require further treatment and may ultimately result in loss of sight .
* Infection- There is a small chance of infection inside the eye after surgery. This may require further treatment and may ultimately result in loss of sight. The operation wull make your eye more prone
to infection, even in years to come. If your eye becomes painful or red or the vision becomes blurred, you should seek immediate medical help
* Cataract – There is a resonable chance that a cataract may develop some years after the surgery. This may require an operation.
* Irritation – Irritation (grittiness) or discomfort in the eye that may persist
* Droopy Eyelid – Eyelid may become droopy on side of operation.
One of the newer types of surgery, a tube shunt, is a flexible glaucoma drainage device that is implanted in the eye to divert aqueous humor (the fluid inside the eye) from the inside of the eye to an external reservoir. The shunt is shaped like a miniature computer mouse with a tube at the end of it. The tube portion enters the front of the eye, or anterior chamber, while the “mouse” or “plate” portion of the implant sits on the surface of the eyeball and is covered by the eyelid. The fluid that collects is then absorbed by the eye’s own veins and transported out of the eye cavity.
The tube shunt is made of silicone or polypropylene, a material that won’t break down in the body. The entire implant is covered with the eye’s own external covering. The procedure is done as outpatient surgery.
Who’s a Candidate for Tube Shunt Procedures?
Traditionally, tube shunts were used to control eye pressure in patients in whom traditional eye surgery to relieve fluid pressure (trabeculectomy) had previously failed, or in patients who have had previous surgeries or trauma that caused substantial scarring of the conjunctiva. Tube shunts have also been successful in controlling eye pressure in other types of glaucoma, such as glaucoma associated with uveitis or inflammation, neovascular glaucoma (associated with diabetes or other vascular eye diseases), pediatric glaucoma, traumatic glaucoma, and others.
Benefits, Risks, and Possible Complications
The vast majority of tube shunt procedures are successful and prevent the progression to blindness that can occur with glaucoma. Nonetheless, it is important for you to understand the risks and benefits before electing a tube shunt surgery. Any of the complications described below can occur even with the best surgical techniques.
Uncommon or rare complications include bleeding inside the eye; infection; fluid buildup behind the retina (choroidal detachment, which is not the same as retinal detachment); double vision with some types of implants; and tube-related complications. Bleeding inside the eye can be a very serious complication; for this reason, some surgeons will ask you to stop all blood thinner medications for at least one week before the surgery. Make sure you ask your general doctor if this is acceptable. If not, a discussion should occur between the ophthalmologist and the general doctor before the surgery.
Infection is another risk. As a precaution, ophthalmologists give antibiotics before, during, and after the surgery in addition to practicing sterile. However, on very rare occasions, infection inside the eye occurs anyway. This can be a very serious problem and may threaten vision. With tube shunt surgery, infection can occur months to years after the actual operation, sometimes requiring shunt removal. Your eye doctor
resume glaucoma medications down the road, or even right after surgery. In addition, sometimes a repeat surgery is required. Also, despite successful surgery, your vision may become worse from continuing degenerative changes in the eye. Cataracts may be accelerated by any of these operations. Fortunately, cataracts are relatively easy to fix surgically.
Tube-related complications can also occur, and some of these relate to placement of the tube inside the eye. If the tube is placed too close to the cornea, it can cause the cornea to swell. This is particularly a problem if you already have a corneal transplant. In some higher risk cases, the surgeon will elect to place the tube in the back of the eye; which means a retina surgeon may perform the procedure alongside your glaucoma surgeon. Another risk entails placing the tube too close to the iris, which can cause it to become clogged with iris tissue. Still another risk is of blood clots developing after the surgery.
Most of the above types of tube complications will resolve with time or with the help of an in-office laser procedure. There is one more type of complication to mention: over time, with or without infection, the tube can protrude through the delicate surface tissues of the eye, or conjunctiva, to where it’s exposed and visible on the eyeball. If that happens, it will require another trip to the operating room so the tube can be re-implanted.
Unfortunately, the damage that is caused by glaucoma is permanent and not yet reversible. Consequently, it is extremely rare for a tube shunt procedure to bring about any improvement in vision. Instead, the main benefit and reason for having the procedure is preventive; i.e., without it, vision may grow worse or, in rare cases, be totally lost. In most cases, doctors will not recommend a tube shunt unless they believe you to be at risk for vision loss. Therefore, for most patients, the benefits of the surgery tend to outweigh the risks, but this has to be evaluated separately for each patient.